1. Field of the Invention
This present invention relates to a light-transmissive shell for a bulb or a lamp and, more particularly, to a light-transmissive shell capable of intensifying an illuminant and wide-angle light transmission.
2. Description of the Related Art
Along with progressive technology of illuminant illuminants, an incandescent bulb, a Hot Cathode Fluorescent Lamp (HCFL), a Cold Cathode Fluorescent Lamp (CCFL), and later a Light-Emitting Diode (LED) as various illuminants are developed unceasingly. Recently, being advantageously featured with power saving, small size, long service life, and solidity, the LED is considered in the field of illuminant technology.
For response to the green energy policy, the tungsten lamp bulbs will exit from all countries in a specified year. The LED bulbs are also considered to be a substitute for conventional bulbs. However, there are gradually some defects in the LED bulbs used as illuminant substitutes for the conventional tungsten lamp bulbs and halogen cup lamps. For example, in the aspects of optical efficiency, service life, and heat sink that are closely linked, the heat sink confined by the volume of a conventional tungsten wide-angle lamp bulb causes E26, E27, and B22 tungsten LED bulbs not to work for brightness of maximum wattage. Further, there is an issue on the LED bulb used with a MR16 halogen lamp. Specifically, if a high illumination bulb is used in an original height of an installed lamp holder, a low illumination LED bulb cannot function for required illumination. Further, the LED bulb cannot function as a PAR-based halogen lamp (in an expanding transparent shell in the form of a reflecting light cup) for central light intensification and wide-angle light transmission. Specifically, the spotlight and wide-area halation projected by the PAR-based halogen lamp on a remote billboard may highlight a theme and a background picture, while existing LED bulbs for the PAR system cannot work for brightness, illumination angle, and halo area.
FIGS. 1 and 2 illustrate two conventional LED bulbs 3 each including a plurality of LEDs (SMD or chip) 301 on a substrate 302, a heat sink 303 with fins 304, a driver 305 provided in a driver pedestal 308 to drive LEDs 301, and a transparent shell 307. A plurality of spaced V-shaped grooves 306 is formed in an upper end of heat sink 303. The spaced angle of grooves 306 depends on a required light-emitting angle, and at least one LED 301 is provided in each groove 306. The shell 307 covers a top of heat sink 303 and has a flat or convex inner surface so that light emitted by LEDs 301 through shell 307 may be at a required illumination angle. However, shell 307 cannot transmit the light emitted by LEDs 301 at a wide-angle. Thus, bulbs 3 cannot function for light projection and wide-area halo illumination at the same time.
FIG. 3 illustrates another conventional LED bulb 4 which includes a plurality of LEDs (SMD or chip) 401 on a substrate 402, a heat sink 403 with fins 404, a driver 405 provided in a driver pedestal 408 to drive the LEDs 401, and a transparent shell 406. The shell 406 covers a top of heat sink 403 and is in the form of a semicircle so that shell 406 may guide the light emitted by LEDs 301 at a wide-angle. However, the volume of LED bulb 4 must be equal to that of tungsten lamp bulb to allow installation in a conventional lamp holder device for embedded tungsten lamp bulbs. The heat sink of maximum volume for the conventional LED bulb cannot work as the tungsten lamp bulb of 100 W LUX in the conditions of photo efficiency and service life for reading at a required illumination angle.
Thus, what is considered by LED suppliers is the fact that the LED bulb is fully the same as the conventional bulb in the requirements of size, service life, luminance, illumination angle, and halation, and may be installed in an original height for the conventional bulb and obtain the light illumination the same as the conventional bulb in the original environments of entertainment places, storefronts, and billboards. Thus, the determined luminance and halation may be achieved. No cost of the lamp device and bulb is spent, such as the costs of lamp device, LED bulb, and wiring, due to insufficient luminance and halation, and no extra loss of business is caused by the business location reconstruction that leads to a business stop.